Conjunctival imporession cytology is a minimally invasive technique used to collect and assess superficial conjunctival epithelial cells from the eye surface. Studies in adults and older children suggest that this technique may be as reliable as biochemical methods in detecting vitamin A deficiency. Vitamin A is essential in the normal differentiation of epithelial cells, including both conjunctiva and pulmonary epithelium. Vitamin A deficiency has been implicated in the development of pulmonary disease in preterm infants. This study will describe the conjunctival cytology seen in preterm infants and correlate these findings with gestational age, chronological age, vitamin A status and pulmonary function.